Item promotion ID dimension
Item promotion ID is the dimension that holds the machine key of an on-site promotion — a banner, hero slot, or merchandised offer — set via the promotion_id parameter on the view_promotion and select_promotion events. It identifies internal merchandising placements, which is a different thing from a coupon (a checkout discount code). Keeping the two apart is essential to attributing sales to promo creative versus discount codes.
What this means
GA4's view_promotion and select_promotion events carry promotion_id, the key for an internal promotional placement, usually alongside promotion_name and creative fields. The item promotion ID dimension surfaces that key so you can measure which on-site promotions get seen and clicked.
It is how internal merchandising — not paid ads — is attributed.
Promotion ID versus coupon
promotion_id identifies a merchandising placement a shopper saw on your site; coupon identifies a discount code applied at checkout. They answer different questions — which creative drove interest versus which code reduced price — and a sale can involve one, both, or neither.
Conflating them double-counts promotional credit. Keep on-site promotion analysis and coupon analysis as separate views.
- Keys an on-site promotional placement
- Set on view_promotion and select_promotion
- Distinct from a checkout coupon code
How it appears in analytics and logs
An item promotion ID value keys an internal promotion. A select_promotion with no following item view suggests the promotion linked somewhere untracked.
Diagnostic use case
Use item promotion ID to attribute engagement and downstream sales to specific on-site promotional placements like banners and hero slots.
What WebmasterID can help detect
WebmasterID can record promotion views and selections keyed by placement first-party, so merchandising performance is measurable without third-party tracking.
Common mistakes
- Conflating promotion_id with coupon codes.
- Leaving promotion_id blank, collapsing all placements together.
- Reusing one promotion_id across unrelated placements.
Privacy and accuracy notes
Item promotion ID keys a merchandising placement, not a person. WebmasterID treats it as first-party content context, never as a visitor identifier.
Related pages
- Promotion dimension
The promotion dimension measures internal promotions — banners, hero slots, on-site campaigns — distinct from paid ad campaigns. GA4 reads promotion_id, promotion_name, creative_name, and creative_slot from view_promotion and select_promotion events. This page explains the model and how it differs from UTM campaigns.
- Coupon dimension
Coupon is the dimension that records the promotion code applied to a purchase. In GA4 ecommerce, coupon exists at two scopes: an order-level coupon on the purchase event and an item-level coupon inside each items entry. Order-level reflects a cart-wide code; item-level reflects a discount on a specific product. Reading the wrong scope, or assuming one implies the other, misstates which promotions drove sales.
- The select_promotion event
select_promotion is the click counterpart to view_promotion in GA4's recommended e-commerce set. You fire it when a user interacts with an internal promotional banner or slot. It carries promotion_id, promotion_name, creative_name, creative_slot, and items so you can join clicks back to impressions and read which on-site placements drive engagement with featured products.
- CTA tracking
Attribute sales to on-site promotions first-party.
Sources and verification notes
- GA4 developer docs — Measure ecommerce (promotions)Documents promotion_id on view_promotion/select_promotion.
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.